Nearly 600 volunteers worked alongside trained professionals Wednesday, but there was no sign of the missing child.

Their efforts were made difficult by cold temperatures and rugged terrain.

"The terrain was woods. It was thick in places," said Max Dudley, a volunteer. "Some places it wasn't that thick, but we took our time and you see the next person, and you look and you look and you look."

Officials said the grandmother and others searched for Casey for 45 minutes before calling 911.

"It's heartbreaking. I have two children so I can only imagine what the family is going through and we're a small community so you don't really expect anything bad to happen here," said Jonathan Ipock, youth pastor of New Haven Church.

Ipock said some of Casey's family attends his church.

"You have so many people volunteering from our community and surrounding areas because they were putting themselves in the shoes of the family," Ipock said. "What would happen if that was one of their children? It's just amazing to see everyone come together to help."

Hughes said his deputies have not ruled out any possibilities in the boy's disappearance, including "abduction or kidnapping." He said they're treating this as a missing child investigation and search.

The area that is being searched is extremely rugged, Hughes said Wednesday afternoon. The family has been cooperating fully, Hughes added.

To clarify: @cravencountync sheriff said they are treating this as a "missing child investigation." They'll be using every resource in looking for #CaseyHathaway moving forward. officials said the terrain is difficult to look through--including thick woods and water #ABC11

"We went through the woods - through the thicket and the briars," said volunteer Donna Harris, a mother of three. "We did it for three-and-a-half, four hours and it was bad. It was really bad out there. If everybody could come and help look for him, it would help. As it got darker, it was scary out there. I just can't imagine a 3-year-old being out there."

Anyone with information should call (252) 633-0498 or the NC State Bureau of Investigation at (919) 662-4500.